The proposed research aims to build a knowledge base about partner violence among young adults, the peak risk group. Specific hypotheses address: (a) developmental pathways from childhood into partner-violence, (b) changes in proximal, contextual circumstances that precipitate incidents of partner violence, (c) relations between partner violence and mental disorders, (d) typological comparisons of partner-violence perpetrators, (e) effects of exposure to parental violence on the children of study participants, and (f) a comparison of findings across sites in two countries. Perpetration and victimization will be measured for both men and women in the longitudinal Dunedin Multidisciplinary Health and Development Study, which follows a representative 1972 birth cohort of 1,000 New Zealand men and women to age 26. Findings will be replicated and extended by measuring men s perpetration and victimization in the longitudinal Pittsburgh Youth Study, which follows a high-risk 7th grade cohort of 500 Black and White urban American men to age 24. Analyses will ascertain relations between the sample members partner violence and independent variables drawn from extensive longitudinal data gathered over many years for these two cohorts, their parents, and their children. The proposed research is expected to contribute: (1) a knowledge base for a developmental theory of the etiology of men s violence against women partners, (2) recommendations for the timing and content of primary preventions and therapeutic interventions, (3) information about contextual factors that may control perpetrators behavior and reduce victims risk, (4) information about how mental health professionals can screen male patients for their risk for perpetration, and (5) information about protective factors that can help children exposed to parental violence. By comparing results across genders, races, and sites in two different nations, the investigators aim to document which findings about young partner violence are robust enough to inform theory, practice, and policy.